It has previously been proposed to provide an exterior building siding of laminate construction wherein a wood core is coated with a protective layer of a colored synthetic plastic material such as polyvinyl chloride. It has also been proposed to provide a building siding in which a thin synthetic plastic sheet is bonded to the outer surface of a rigid foam plastic layer which in turn is bonded to the outer surface of the core panel. Patents of this character are part of the following list of prior art patents which I incorporate by reference herein.
U.S. Pat. No. 2,277,752 Frey PA1 U.S. Pat. No. 3,350,257 Hourigan et al PA1 U.S. Pat. No. 3,408,786 Snyker PA1 U.S. Pat. No. 3,866,378 Kessler PA1 U.S. Pat. No. 4,146,662 Eggers et al PA1 U.S. Pat. No. 4,478,415 Shaffer et al PA1 U.S. Pat. No. 4,788,808 Slocum
In these prior art patents, the plastic outer faces have been either applied in the form of a coating or bonded film which was not, first of all, molded to the configuration of the core. To my knowledge, no one has successfully commercially formed such a product by molding a sheet or film of synthetic plastic to the precise shape of the core, utilizing the core as the mold surface, and differential pressure drawing the plastic sheet to the core with such definition that the grain of the board is defined in the plastic outer covering.